Shinobi of the Underworld
by 27Tsu18Kyou
Summary: The child's doe brown eyes looked up into worried and relieved ones. No one says a word until small arms wrap around the man's neck. "Arigato, Nii-san," he mumbled in embarrassed gratitude. The man of multicolored hair smiled warmly at the child. "You're welcome, little one." Crossover, Familial!Naruto, AU, Godlike!Naruto, Strong!Tsunayoshi, Rated M for language
1. Chapter 1

_The city of Namimori was quiet at the time. Snow littered the ground in big and small clumps. Sidewalks were barely visible under the loose, wet snow. The sun was covered by the clouds though it peaked through every once in a while._

_A man was silently padding down the street, nearing the park. There was nothing really unique about him for he was covered from head to toe in a dark cloak to stave off the biting chill. The only thing visible on his person was blonde, red, and black hair. This was uncommon in Japan but no one bothered him._

_A child and his mother were walking in his direction when the 5-year-old dropped one of the oranges that were in his small grocery bag due to slipping a bit on the ice._

_"Ah! The orange!" the boy cried out. The brunette sat down the bag and ran to get the rolling fruit._

_"No! Tsu-kun!" the mother screamed in panic. She dropped her groceries as she stood frozen, watching an incoming van approach her child by the second._

_Everything seemed to play out in slow motion._

_30 yards_

_The boy looked up with the orange clutched in his tiny hands._

_15 yards_

_His eyes widened as he froze in fear._

_10 feet_

_He heard his mother scream for him._

_5 feet_

_The van honked noisily._

_3 feet_

_The van began to swerve and lose control._

_1 foot_

_CRASH!_

_The van collided with a nearby street lamp._

_People rushed out of their homes to see what happened in the small, quiet town of Namimori. Doing so caused them to become mortified by the horrific scene of the driver hanging out of the windshield with half of their body crushed between the steering wheel and the seat._

_The mother who screamed for her child looked around frantically for the small boy. That's when she spotted the man that she saw earlier now across the street with his back to her._

_Said man loosened his hold on the terrified boy and rubbed his fluffy brown hair. The boy shakily looked into into blue eyes that screamed warmth and concern._

_"Are you alright, little one?" a soft timbre reverberated through his ears and body. The boy gave a trembling nod with tears at the edge of his eyes. The child's doe brown eyes looked up into worried and relieved ones. No one says a word until small arms wrap around the man's neck._

_"Arigato, Nii-san," he mumbled in embarrassed gratitude. The man of multicolored hair smiled warmly at the child. "You're welcome, little one."_


	2. Chapter 2

"_Arigato, Nii-san," he mumbled in embarrassed gratitude. The man of multicolored hair smiled warmly at the child. "You're welcome, little one."_

* * *

Later that day, after the male was invited to the duo brunette's home, who was revealed to be a Naruto Uzumaki Namikaze, the three sat at the table enjoying dinner.

"This is excellent, Nana-san." Naruto complimented. Said woman blushed.

"Oh, thank you very much, Naruto-san! I'm glad you like my cooking!"

"Mm! I think you could even rival some professional chefs. Oh, and by the way, you could just call me Naruto. -san makes me feel old."

"Hai, Naruto-kun." Nana smiled. The tan male did the same before he turned his attention to the silent toddler.

"Is something wrong, Tsunayoshi-kun?"

Tsuna jumped a bit before clenching his fists upon his thighs.

"A-ano… Y-you're not f-from here…r-r-right…?" The boy timidly asked. Naruto smiled encouragingly and nodded.

"That's right. Why do you ask?"

The child grew silent for a moment before peaked up at the man with a wavering smile.

"I-I was w-w-wondering if you would l-like to s-stay with u-us? I-if kaa-san don't mind." He mumbled the last part. Nana gushed at that and immediately turned excited eyes onto the multi-hair colored man.

"Ah! what an amazing idea, Tsu-kun! Please, won't you stay with us? I really wouldn't mind. It gets lonely at times with just me and Tsu-kun here. It would be nice to have more company. Plus, I think my Tsu-kun already likes you." Nana rambled. Tsuna blushed hotly which only caused Naruto to chuckle lowly at the shy child. It really would be a nice change of pace if he stayed with the small Sawada family. It's been so long since he'd had any contact with the outside world, and he feels things would soon get interesting.

"I think I will take you up on that offer. But wouldn't your husband be upset at another male living with his family?" Naruto asked with a tilt of his head. Nana waved a petite hand in his direction, "I don't want to cause any trouble."

"I'm sure he wouldn't mind. Besides, he's a hero! He travels the world mining oil!" Nana beamed with a blush across her cheeks. Naruto raised an eyebrow to that and shrugged it off. He's heard and seen many other odd things in his life.

"Well, if you don't mind…" he trailed off before standing. He grabbed his empty plate and grabbed the others. He went to the sink and began to wash dishes.

"What are you doing, Naruto-kun? You don't have to do the dishes! You're a guest, remember?" the older Sawada fretted. Naruto smiled over his shoulder.

"Don't worry about it, Nana-san. After all, I will be living here from now on. It's the least I could do." He reassured her. Nana brightly smiled with Tsuna at her side. The boy walked up to him and tugged on the, mostly, blonde's pants.

"U-um… C-can I help?" He asked with hopeful eyes. Naruto grinned and dried his hands off on a rag. He lifted the small brunette up on the counter next to him.

"Sure! You can dry–"

"And I will put the dishes away." Nana cut in on the other side of of the brunette with a wink. Tsuna and Naruto smiled at her and they all proceeded to wash the dishes with smiles and laughs.

This was the beginning of a new life for one Naruto Uzumaki-Namikaze.


	3. Chapter 3

_This was the beginning of a new life for one Naruto Uzumaki-Namikaze._

* * *

It's been 8 years since that fateful day and Naruto has honestly enjoyed every minute he was with the two Sawada. He found a younger brother, almost son, within the small doe-eyed boy, and, almost, a mother within the bubbly woman. Things were going so well until he had noticed throughout his stay there that the mother and son duo were being targeted. Of course he didn't let them(the assassins) go with their lives, but that just gave him an even more incentive to protect the two from harm. He found himself becoming attached and protective. So in order to curb some of his paranoia of the two precious lives being stolen away, he subtly taught Nana how to wield her many knives, which also helped her cook even more delicious food. He had Tsuna do light training for he noticed how the boy had gained a detestable name for his clumsiness. The boy was taking to the "ninja training" like a fish to water. But he (Tsuna) decided not to draw attention to himself for using his training. He decided to stay "dame" as one of the first lessons to being a ninja is having deception become your greatest weapon. Naruto approved but he kept up with the boy's training when at home.

Currently, Naruto was not home when Tsuna met his new home tutor. The man had felt something was going to change that day, so he decided to stroll through Namimori before his, mostly, peaceful days came to an end.

He had somehow ended up at Namimori-Chuu while in thought. He spotted a student who dressed differently, had raven hair, and piercing gray eyes. The teen also noticed him and narrowed his eyes into a glare at the strange man in his territory.

"What are you doing here, herbivore." The raven-haired teen practically demanded an explanation. Naruto cocked his head to the side as he studied the boy that was releasing his bloodlust.

"Nothing much, child," said 'child' twitched to that, "merely taking a stroll." Naruto casually informed. The boy growled and whipped out two metal poles from somewhere on his person with a glower.

"Herbivore, kamikorosu."

With that, the raven went on the attack. He went to give the insolent man a strike to the face, but he was easily dodged. The teen swung around in order to jab the man in the back with the end of one of his tonfa. He was caught off guard when the weapon was stopped in its tracks.

The red and black streaked blonde calmly gazed down at the fuming boy before curling the ends of his lips.

"You're pretty interesting. What's your name?" Naruto asked. The raven narrowed his eyes and observed the mysterious male. He did not seem to actually mind that someone younger than him had the intention of beating him. The man even smiled at the fact!

"... Hibari Kyouya." The boy reluctantly gave away. The male smiled wider and released his grip from the tonfa.

"Nice to meet you, Kyouya-san. You're pretty strong for someone your age. Not many are like you." Naruto commented. The now named Hibari Kyouya put away his weapons as he silently watched the lax man.

"Hn. That is because I am not a herbivore." He bluntly stated. Naruto chuckled in amusement before he was cut off by a shout. He and Hibari looked over to see a certain brunette in his boxers with a mysterious flame on his forehead. Naruto rapidly blinked his eyes before covering his mouth with his hand. The skin by his eyes crinkled and his shoulders shook. Kyouya raised an eyebrow at the, admitted, carnivore.

"Pfft! I wonder - haha! - what has brought this *snicker* on?" Naruto managed through his almost quiet peals of laughter. Hibari's brow twitched in annoyance and he jabbed the man in his side with the end of his tonfa.

"Stop laughing, carnivore."

Naruto removed his and from his mouth and gave the teen a warming smile.

"My name's Naruto. Naruto Uzumaki-Namikaze. Not 'carnivore'." He informed The raven raised his brow again as the man walked towards the crowd of herbivores.

"...Strange carnivore."

* * *

Tsuna had just got out of his Dying Will state and he was immensely embarrassed. He had confessed to his crush IN HIS BOXERS! Oh, he doesn't know what could make this day even worse.

"Maa, Tsuna. What have you gotten yourself into this time?" An amused voice piped up from beside him. Tsuna snapped his neck toward the man and Naruto was surprised the boy didn't get whiplash.

"N-N-Naru-nii!?"Tsuna exclaimed in surprise.

"Ohayo, Tsuna-kun." Naruto waved Tsuna stuttered and blushed bright red.

"W-w-w-what are you do-doing here?!" The teen sputtered as he used his arms to try to cover his chest. Naruto laughed and ruffled the boy's already untamable hair.

"Nothing you should worry 'bout, chibi–"

"Stop calling me that!" Tsuna cut in.

"–Just taking a walk around town." The mostly blonde continued as if he wasn't interrupted. The Brunette hung his head in defeat.

"Ciaossu." A squeaky voice greeted. Naruto looked a bit of a ways away from the mumbling boy to see a baby in an expensive suit with an orange-banded fedora and a green chameleon…?

"Uh… Hi?" Naruto awkwardly greeted back. The dark-haired baby smirked as he watched the perplexed blonde tilt his head to the side. "Who're you?"

"My name is Reborn. I'm Dame-Tsuna's new home tutor. Who are you?"

To Naruto, that was more of a command, and he raised an eyebrow in wonder but shrugged it off.

"My name's Naruto Uzumaki-Namikaze. It's a pleasure to meet you, Reborn-san." Naruto slightly bowed. Reborn stayed silent as he watched the blue-eyed man interact with his new student. He felt that something was off with the blonde and know he should keep an eye on this 'Naruto'.

Before the boy could be late for class, Reborn threw the boy's school bag to him along with his clothes that had been sewn up. Naruto waved after his brother before turning to the hitman.

"Sooo… What are you going to do now?" He asked.

"I have to watch my student in his everyday life. As is the job of a tutor. Ciao." Reborn informed before he jumped away and disappeared behind the school gates. Naruto just stared and sighed. He looked up to the wide sky and thought aloud.

"Things have gotten more interesting. Let's show them who you really are, ne?"


	4. Chapter 4

**Sorry for the late update! I've been working on a few other fics, including this one. **

**Enjoy!**

* * *

It was now after school and Tsuna felt exhausted. Not the kind of tiredness he normally have when training with his father (he only calls Naruto that when at home or on his vulnerable days), but a deep seeded tiredness that makes one think that there's no possible way things will get better. The brunette was slumped on the couch next to the blonde who was munching on ramen.

"How was school?" Naruto threw out. Tsuna groaned with a depressing air about him. Gloom surrounded him as he managed to respond.

"Ugh..." He grunted as he rolled over to rest his head on his father-figure's lap. Naruto smiled, amused, and sat his empty bowl on the low table and ran his fingers through his pseudo-son's unruly hair.

"Oh, really? A little more in depth, please?"

"Mmgh...fight...weird...underwear...Kyoko..."

"Uh-huh. That must've been some day, ne? Well, I have a feeling that this won't be the end of it, chibi. A lot of things are coming your way, but you shouldn't worry. I'll be with you the whole time —every step of the way." He spoke softly. Tsuna's eyes became droopy as a small, tired smile appeared.

"Arigato, Tou-san..." the teen trailed off into sleep. Naruto kept silent as he caressed the brunette's hair. He understood why Tsuna thanked him and couldn't help but feel grateful if a little upset with Iemitsu Sawada. He knows who the father of his chibi is and he could understand why he is doing what he is, but that does not excuse him for practically neglecting his family. The least the man could've done was visit more often and not make Nana cry at night because of how miserable her married life is, or make Tsuna feel as if his birth father didn't care about him. Naruto will have some words with the other blonde.

Reborn watched silently from the threshold to the dining room. He wore a frown on his face as he observed the interaction between his new student and the strange blonde. The Sun Arcobaleno could feel the level of danger from the man, but he could not feel any hostility from him. Besides, why hasn't that idiot Iemitsu told him that there was someone else living with his family?

* * *

**FLASHBACK**

_Tsuna was nearly seven-years old when Nana came in the living room with a squeal. Naruto and Tsuna was sleeping on the floor with paint covering their hands and clothes. The two were having a blast with painting and other activities of the day. Now, they were both tuckered out and in the blissful land of sleep._

_Not anymore._

_The squeal of the matriarch of the household caused both to rouse from their dreams. Tsuna whined and turned over to block out the sound of his mother's excitement. Naruto cracked open an eye before having to close it to yawn. He peaked up at the joyful brunette who was clutching a letter between her fingers. _

_"What is it, Nana-san...?" Naruto questioned sleepily. Nana rushed over to the two paint-splattered males and shoved the letter into his face. Tsuna finally decided to wake up fully with a big yawn. He rubbed his right eye as he curiously waited for his mother's response. _

_"Iemitsu will be coming home soon!" The gushing brunette squealed with a blush. Naruto froze at that and took on a pensive look. He knew it would be bad news if the husband of Nana came home to see him in his house with his family. Naruto has to find some way to not let the man know that an intruder, let alone another man, was living here._

_Naruto made up his mind._

_"Nana-san," said woman was cut from her thoughts, "I do not think it would be wise of me to stay any longer."_

_Nana was surprised. _

_"Why is that, Naruto-kun? I'm sure Iemitsu wouldn't mind." She tried to reason with him. Tsuna also looked up to him with scared and panicked eyes._

_"No. I think it would be best if I did not show myself to him. It would just cause trouble and I do not want your marriage to be strained over the fact that I am living here —another man— in your house." Naruto explained as he stood up from the floor. Tsuna clamoured to his feet and clutched at the blonde's pants. He turned his teary eyes up to him when he caught the other's attention._

_"Iie! Please don't go! I-I don't want you to leave!" He begged. Naruto gave a soft smile and lifted the boy into his arms. _

_"I don't want to either, Chibi, but I have to."_

_"B-b-but...!"_

_"Hey, hey! It's okay. I'll be back when he leaves. But you have to promise me you won't tell him that I was here, okay? Can you do that for me?" Naruto asked as he wiped a stray tear from the devastated child. Tsuna whimpered but nodded his head. Naruto smiled and placed a small kiss to the boy's forehead. _

_"Thank you, Tsu-kun. Now, no more tears. Where's my brave lion?" He asked. Tsuna sniffed and gave a fierce (read: cute) face with determination swimming in his eyes. Naruto smiled brightly and used one of his hands to ruffle the boy's soft hair._

_"There he is! Now, behave for Nana-san, okay? I'll be back before you even know it." Tsuna nodded and gave Naruto a big hug. When he let go, the mostly-blond turned to a saddened Nana. He gave her a small smile a placed a hand on her shoulder. _

_"Don't look like that, Nana-san. This is nothing, really. Just...keep my existence a secret for now. Focus on him coming home and it won't even seem like I was here." Naruto instructed. Nana clasped her hands to her chest in worry. _

_"But where will you go? You've been living with us for a while and I would hate to leave you out on the street." _

_"Don't worry so much. I have the perfect hiding space and will be okay on my own. It won't be the first time I've had to hide out. Now," he set Tsuna on the floor, "I guess I should get to work in erasing my presence. It's not really hard to do."_

**FLASHBACK END**

* * *

"Hey. Tsuna. It's time to wake up. Dinner's almost ready." Naruto shook the teen. Said brunet groaned and sat up while rubbing the sleep out of his eyes. He yawned and looked at the clock on the wall.

6:32 pm.

Blink. Blink.

…

"HIIIIEEEE! WHY'D YOU LET ME SLEEP IN SO LATE? NOW I'LL BE UP ALL NIGHT DOING HOMEWORK!" Tsuna panicked. Naruto raised an eyebrow at his reaction and huffed in amusement.

"Oh? Like the time when you were supposed to be studying for a math test but instead you chose to take a nap that lasted throughout the whole night and barely managed to get to school on time?" He mused. Tsuna blushed and glared at the smirking man.

"That was your fault and you know it! Mou~ Why do this always happen to me?" The younger male moaned pitifully. Naruto snickered and ruffled his hair.

"You worry too much, Chibi. You'll get to your homework in time." Naruto comforted as he got up to head into the dining room. Tsuna sighed and followed him inside.

In the room, Reborn was drinking an espresso and watching them from the corner of his eye. He kept a blank face as he observed the two setting up the table for the food to be placed. They were making light talk as Nana put the finishing touches to the dishes.

"Alright, minna! Dinner is ready!" She called attention with a big smile. Naruto went over and helped her distribute the food.

"Moouu~ Naruto-kun~! Just have a seat! I'll give you your food really soon." Nana pouted. Naruto had on a sheepish smile.

"But you know I don't like for you to everything by yourself, Nana-san." He protested. Nana started lightly pushing him toward the table and made him sit next to Tsuna.

"It's fine, Naruto-kun. Besides, a host always serve those at the table —especially when we have a new guest. I've told you that since day one." Nana lightly lectured. Naruto gave in with a sigh as Tsuna covered up a chuckle. This brought the attention of the Hitman.

"'Since day one'? What are you talking about, Maman?" He questioned the older Sawada. Nana turned to the infant with a beaming smile that soon turned nostalgic as she recalled to past.

"Well, Naruto-kun has been living with us for 8 years now. Tsu-kun and I were on our way home from grocery shopping when Tsuna ran into the street to catch an orange he dropped. There was a huge van heading toward him when I noticed he left my side. I called for him and was about to rush out to get him when I knew I wasn't going to make it. All I remembered hearing was a blaring beep from the van and a crash. I thought the worst when I didn't see Tsu-kun anywhere and nearly hysterical. I had noticed Naruto-kun not too far from me because I remembered seeing him on the other side of that rest due to his odd hair and saw him holding something. When he opened his arms, Tsu-kun was there: shaken, but okay. Little Tsu-kun invited him over and he's been staying with us since." Nana finished recalling. Reborn stared at Naruto as said man softly smiled and Tsuna blushed with a smile as well.

_'Hmm… Interesting. This is something to definitely report to Nono. But I probably should inform him that Iemitsu should not be aware of a stranger in his home. Besides,'_ at this he smirked, _'I can't wait to see his expression when he finds out on his own.' _

"Now, why don't we dig in?" Nana suggested to which Naruto and Tsuna both clasped their hands together and replied with an 'Itadakimasu!' Reborn did his more quietly and the quartet started eating.


End file.
